you get an auto bid if you win your conference (p5 confs) and are in top 10. i'd feel pretty confident that any p5 conf team with an 12-1 record and conf champ would be top 10, including purdue.
I personally don't necessarily LIKE qualifiers that are outside the team's control such as polls, but I could get behind it.
However I'd pair that maybe with a sliding scale exclusion as an incentive to schedule tougher OOC. Top 10 if you play 9 P5 teams, top 15 in you play 10 P5 teams, and maybe top 25 if you play 11 or more P5 teams. Or something similar to that.
That makes it even more important to schedule up OOC, but also allows you wiggle room to lose high-profile OOC games without a huge penalty.
I.e. let's say Purdue wins the conference instead as 10-3, and sits at 18th. But their losses were two of their 9 conference games, and they scheduled Clemson and UCLA OOC, beating UCLA handily but losing to Clemson. I think in that case they shouldn't be excluded for losing tough OOC games.
If you make it "top 10", it makes it even more likely that teams will schedule patsies OOC so that they minimize total losses on the schedule, because voters are lazy and typically will rank a 1-loss team ahead of a 2-loss team, ahead of a 3-loss team, regardless of the quality of those losses.